Heart failure (HF) is an important public health problem that affects approximately 6.6 million Americans. Despite improvements in cardiac care, it remains the leading cause for hospitalization among Medicare patients and the only major cardiovascular disease whose mortality rate has remained essentially unchanged over the past decade. This failure to improve HF outcomes may be due, in part, to unrecognized and/or inadequately treated depression that is highly prevalent in HF patients. Yet while new HF treatment guidelines advocate routine screening for depression, this recommendation is unlikely to be widely adopted without trial evidence that depression care improves outcomes and efficient methods to provide it. Collaborative care strategies are being increasingly utilized t improve care for HF and other chronic medical conditions, and we recently demonstrated its clinical and cost-effectiveness at treating depression following coronary artery bypass graft surgery. Yet it may be impractical for health care delivery systems to support separate treatment programs for HF and depression. Thus we are encouraged by emerging evidence indicating blended collaborative care strategies that target both psychiatric and physical conditions produce greater improvements in mood symptoms and control of cardiovascular risk factors than programs focused solely on depression to propose testing a novel adaptation that could be provided in routine care. The Specific Aims of this Project are to: (1) evaluate the effectiveness of a telephone-delivered blended collaborative care intervention for treating HF and depression that could be adopted into routine clinical practice if proven effective; and (2) advance our understanding of the moderators and mediators of depression treatment on clinical outcomes. We will screen hospitalized patients with systolic HF for depression, and then randomize 625 who screen positive and have at least a moderately elevated level of depressive symptoms at two-weeks following hospital discharge to either: (1) collaborative care for treating both HF and depression (blended); (2) collaborative care for treating HF alone (enhanced usual care (eUC)); or (3) their doctors' usual care (UC). Additionally, we will enroll 125 non-depressed HF patients to better evaluate the benefits derived from treating depression (total N=750). Our co-primary hypotheses will test whether blended collaborative care can produce at 12-months follow-up a: (A) 0.50 effect size (ES) or greater improvement in health-related quality of life (HRQoL) vs. UC; and (B) 0.30 ES or greater improvement in HRQoL vs. eUC. Secondary hypotheses will evaluate the effects of our blended intervention on mood, functional status, adherence with guideline-consistent care, incidence of cardiovascular events, health care utilization, and costs. Improving chronic illness care for medically complex patients is one of the major challenges facing medicine today. We propose to test the effectiveness of an innovative, efficient, scalable, and sustainable intervention that could transform the way HF and other cardiovascular disorders are treated in routine practice.